Selective separation of luteo cobalt from ammoniacal solutions containing divalent copper and/or divalent nickel by preferential adsorption on a chelating resin



United States Patent 3,082,081 SELECTIVE SEPARATION OF LUTEO COBALT FROM AMMONIACAL SOLUTIONS CONTAIN- ING DIVALEN-T COPPER AND/0R DIVALENT NICKEL BY PREFERENTIAL ABSORPTION ON A CHELATING RESIN Joseph H. Howe, Freeland, and Leo R. Morris, Midland,

Mich., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed May 19, 1960, Ser. No. 30,107 3 Claims. (Cl. 75-119) This invention concerns a method for separating cobalt from copper or nickel or from copper and nickel. More particularly, it concerns a method for separating cobalt from copper and/or nickel in an ammoniacal medium wherein the cobalt is in the luteo form by adsorption on a chelating resin wherein the cobalt is preferentially adsorbed by the chelating resin and the copper and/ or nickel are thereby readily separated from the cobalt. More particularly, the method of this invention consists in separating cobalt from copper and/ or nickel by adsorption on a chelating resin in the ammonium salt form having carboxymethylthio, -SCH CO H, or 1,2-dicarboxyethylthio, -S-CH(CH CO H)CO H, substituent groups wherein cobalt is preferentially held and thereafter eluting and simultaneously regenerating the loaded resin with a mineral acid wash to recover a cobalt concentrate.

In the past use of ion exchange and chelating resins, various procedures have been developed for concentrating metals as their conventional or complex ions. In the process of this invention, a separation has been developed wherein the order of selectivitiy for cobalt, copper and nickel has been reversed from that of previously known procedures wherein either copper or nickel is bound by the separating means in preference to cobalt. This newly discovered preferential adsorption of cobalt is quite advantageous in the metals separation of ore leach liquors containing binary or ternary luteo cobalt mixtures of the above metals where it is desired to hang up or concentrate the cobalt, particularly when the cobalt is present in small amounts relative to copper and/or nickel. The use of such a cobalt selective resin lowers the frequency of regeneration when a low-cobalt ore leach liquor is to be processed and thereby reduces operating costs.

The process of this invention employs a chelating resin of the groups of resinous polymeric (vinylbenzylthio) acetic acid,

crosslinked with about 1-8 mole percent, total polymer basis, of a conventional crosslinking agent such as divinylbenzene, divinyltoluenes, divinylnaphthalenes, divinyl ethyl benzenes, divinylxylenes, diacrylate esters, dirn'ethacrylate esters, diallyl esters and the like. The aryl nucleus can also be substituted with non-reactive substituent groups, e.g., lower alkyl up to 3 carbon atoms and halogen. These resins will be referred to hereafter as (thio) acetic and (thio)succinic chelating resins. They are used in the ammonium salt form.

In practice, an ammoniacal solution containing a mineral acid salt of luteo cobalt, divalent copper and/or divalent nickel is contacted at room temperature with a (thio)acetic or a (thio)succinic chelating resin in the am- "ice case, contact time is varied as desired for a wante separation. In either case, a simple test run suffices to de termine the contact time of a metals solution with a give] chelating resin. The preferentially adsorbed cobalt, to gether with a minor amount of copper and/or nickel, i thereafter removed with a dilute mineral acid eluant advantageously 1-molar hydrochloric acid. The prefer ence of the given chelating resins is shown when a calcula tion is made of the metal preference ratio, hereafte M.P.R. The M.P.R. is the ratio of the molar concentra tions of the metals in the resin eluate corrected for Th4 molar concentration in the original metal liquor, i.e.,

B A where X (A )-=molar concentration of metal A in resin eluate (B )-=molar concentration of metal B in resin eluate (A =molar concentration of metal A in original meta liquor, and

(B :molar concentration of metal B in original meta liquor The M.P.R.s for a ternary system can be derived b combining the M.P.R.s calculated for any two pairs 0 the three metals in the system. With batch (equilibrium operation, the M.P.R.s of CozNizCu approximate 5:1: with a (thio)acetic chelating resin crosslinked with 1 weight percent divinylbenzene and approximate 20:3: wih a (thio)succinic chelating resin crosslinked with 1 weight percent divinylbenzene. With column operatior the M.P.R.s of Co:Ni:Cu approximate 12:1 :1 both for (thio)acetic and a (thio)succinic chelating resin whici are 4 percent crosslinked with divinylbenzene.

The (thio)acetic and (thio) succinic chelating resins ma be prepared by reacting a water-wet poly(vinylaryl sul fonium) anion exchange resin, as described in US. Paten 2,895,925 and in U .S. patent application Serial Nr 769,545, filed October 27, 1958, with a stoichiometri equivalent of disodium thioglycollate or of trisodium mei captosuccinate, respectively, by heating the reactants o a steam bath for a time suflicient to displace sulfide wit carboxymethylthio or with 1,2-dicarboxyethylthio group: respectively. This generally takes from 1 to 2 days. Th resulting (thio)acetic or (thio)succinic chelating resir usually in the sodium salt form, is separated from the re action medium, rinsed with water and with concentrate hydrochloric acid and given a final water rinse. Befor use, the resin is changed to the ammonium salt form.

The following non-limitative examples describe con pletely specific embodiments of the inventive process an set forth the best mode contemplated by the inventors c carrying out their invention.

EXAMPLE 1 A small quantity (1.6 g.) of a (thio) acetic chelatin resin, 2 percent crosslinked with divinylbenzene, pn pared as described above, was equilibrated in ca. l-molz NH OH for an hour. The NH OH was decanted and tl resin was contacted with an ammoniacal metal liquor the following composition:

CuSO -5H O 0.02 NiSO '6H O 0.03 [CO('NH3)6]2(-SO4)3 in an aqueous solution of l-molar NH OH.

After 24 hours of solution-resin contact with constai agitation, the excess metal solution was poured oil ar the resin was Washed several times with l-molar NH O followed by several water washes. There was no obser' able removal of metals by these washes. The resin w:

eluted with l-molar hydrochloric acid and the eluate was analyzed polarographically.

EXAMPLE 2 The procedure of Example 1 was repeated with a (thio)succinic chelating resin, 4 percent crosslinked with divinylbenzene, prepared as described above.

Following Table I gives results of the evaluations of Examples 1 and 2.

Table I EQUILIBRIUM RESIN EVALUATION FOR SEPARATION OF AMMONIACAL Cu++-Ni++-C+++ (LUTEO) Dry Resin Metal preference ratio Capacity Resin weight vol.

Cu++ N1++ Co Mmole/g. Mmo1e./ml.

Po1y[(vinylbenzylthio)acetic acid] X2 1.6 5.4 1.2 1 5. 3 1.2 0. 4 1oly[(vinylbenzylthio)succinic acid] X4 0.5 1. 8 1 2. 6 20.1 3.0 0.9

1 Equilibrated in ca. l-molar NHiOH. 2 X=crosslinked, number=pereent combined divinylbenzene.

EXAMPLE 3 EXAMPLE 5 The procedure of Example 4 was repeated with a (thio)acetic chelating resin.

The analyses of the eluates of Examples 4 and 5 are given in following Table III.

Table III COLUMN RESIN EVALUATION FOR SEPARATION OF AMMONIACAL Cu++--Ni+"C0 (LUTEO) Dry Resin Metal preference ratio Capacity Resin weight Vol.

Cu++ Ni++ :Co+++ Mmolejg. Mm01e./ml.

Po1y[(viny1bcnzy1thio) acetic acid] X4 3. 5 11.0 1 1. 2 11.6 1.5 0.5 Po1y[(vinylbenzylthio)suceinic acid] X4.. 3. 8 11.3 1 1.3 11.1 1. 9 0. 6

1 Equilibrated in ca. l-molar NHiOH. 1 X =crosslinked, numbcr=percent combined divinylbcnzene.

Table II PARTIAL EQUILIBRIUM RESIN EVALUATIONS FOR SEPA- RATION OF AIVIMONIACAL Co' flLUTEO)Ni+ Luteo C0+++Ni++ Resin Co+++lNi++ Capacity, pref. ratio Mmole/g.

(Thio)suecinie acid X1 k 12. 4 1. 4 (Thio)acetie acid X1. 13. 4 0.6

1 One-hour equilibrium test with approximately equimolar Co(NHa)a+++Ni++..

2 X1=erosslinked with one mole percent divmylbenzene.

EXAMPLE 4 The (thio)succinic acid resin referred to in Example 2 was evaluated for a column separation of the In these examples only enough metal solution was contacted with the resin to indicate a separation of the Co+++(luteo) from the Cu++ and Ni++, and, therefore, the resin was only partially equilibrated. Flow rates varied from ().10.3 gal./ft. /rnin.

What is claimed is:

1. Method for separating luteo cobalt from copper and nickel by contacting an ammoniacal solution of luteo cobalt also containing at least one member of the group consisting of divalent copper and divalent nickel with a chelating resin of the group consisting of resinous polymeric (vinylbenzylthio)acetic acid and resinous polymeric (vinylbenzylthio)succinic acid, crosslinked with about 1 to 8 mole percent, total polymer basis, of a crosslinking agent whereby the luteo cobalt is preferentially adsorbed and the cobalt is concentrated on the resin and eluting the loaded resin with a mineral acid to remove a concentrated cobalt tfraction from the resin.

2. The method of claim 1 wherein the loaded resin is eluted with one-molar hydrochloric acid.

3. Method for separating luteo cobalt from copper and nickel by passing an ammoniacal solution of luteo cobalt also containing at least one member of the group consisting of divalent copper and divalent nickel through a column of an ammonium hydroxide-equilibrated chelating resin of the group consisting of resinous polymeric (vinylbenzylthio)acetic acid and resinous polymeric (vinylbenzylthio)succinic acid, crosslinked with about 1 to 8 mole percent, total polymer basis, of a crosslinking agent whereby the luteo cobalt is preferentially adsorbed and the cobalt is concentrated on the resin and eluting the 3,082,081 5 6 loaded resin with a mineral acid to remove the cobalt as OTHER REFERENCES a concentrate and simultaneously to regenerate the resin. Hale: Research paper V01. 1956 pages 104408 (en.

v titled Ohelating Resins), published by Chemical Research References Clted m the file of thls patent Laboratory, Teddington, England, Ion Exchange Digest UNITED STATES PATENTS 5 Gregor et al.: Industrial and Engineering Chemistry 2,848,322 Conn et a1 Aug. 19, 1958 V0 44, N0. 12, 1952, pages 2834-2838 (entitled Chelatc 2,964,276 Hazen Sept. 27, 1960 Ion Exchange Resin), Ion Exchange Digest. 

1. METHOD FOR SEPARATING LUTEO COBALT FROM COPPER AND NICKEL BY CONTACTING AN AMKONIACAL SOLUTION OF LUTEO COBALT ALSO CONTAINING AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF DIVALENT COOPER AND DIVALENT NICKEL WITH A CHELATING RESIN OF THE GROUP CONSISTING OF RESINOUS POLYMERIC (VINYLBENZYLTHIO)ACETIC ACID RESINOUS POLYMERIC (CINLBENZYLTHIO)SUCCINIC ACID, CROSSLINKED WITH ABOUT 